The main chip of a computer, which carries out instructions. People also use the word for the whole system box, though that is not strictly correct.

CPU full form: Central Processing Unit

Q: What is the full form of CPU?

CPU stands for Central Processing Unit.

How to say it: letter by letter.

CPU stands for Central Processing Unit. It is the part of a computer that carries out the instructions of programs. It is often called the brain of the computer, and also simply the processor.

What it does

Every program is a long list of very simple instructions: add two numbers, compare two values, move a piece of data, jump to another instruction. The CPU fetches each instruction from memory, works out what it means, and carries it out, billions of times a second. This is called the fetch, decode and execute cycle.

The parts of a CPU

ALU, the Arithmetic Logic Unit, does the calculations and comparisons.
CU, the Control Unit, directs the other parts and keeps the steps in order.
Registers are tiny, very fast stores for the values being worked on.
Cache is fast memory that keeps recently used data close at hand.

Words used when comparing processors

Cores: a modern CPU has several processing units in one chip, so it can do several things at once.
GHz, gigahertz: the clock speed, in billions of cycles a second.
32-bit and 64-bit: how much data the processor handles in one step.

The CPU is not the box

In many schools and offices in India the tall cabinet of a desktop computer is called "the CPU". Strictly, that box is the system unit or cabinet. The CPU is one small square chip inside it, fixed to the motherboard under a fan. The box also holds the memory, the storage drive and the power supply. In an examination, give the strict meaning.

Related full forms

GPU: Graphics Processing Unit.
RAM: Random Access Memory.
SoC: System on a Chip, the kind of processor used in phones.

More computers and internet full forms

All computers and internet Next: RAM explained

Check what matters. These pages explain names and terms in general. Rules, dates, fees and limits change: take them from the official body. Read on 12 November 2026.